U.S. Pat. No. 6,753,662 describes a compact THz source based upon a small linac and an undulator. Such a source can be designed to produce both narrowband and wideband THz radiation.
As described in this patent, a compact source of intense THz radiation comprising a short bunch, low energy particle beam source, an accelerator cavity and an electromagnetic wiggler or undulator. The application of state-of-the-art superconducting accelerating structures and beam recirculation allows such a THz radiation source to have a small footprint and high average intensity without the need for the large equipment necessary to produce the large charge per bunch generally associated with the production of THz radiation. Consequently, low emittance electron beams can be used to produce emitted THz radiation of high yield average brilliance.
As described in the '662 patent, the undulator utilized is of conventional design and construction and demonstrates the following properties: undulator period of 3 cm, number of oscillations up to 50 and magnetic field strength up to 1 Tesla.
While such a device/system provides entirely satisfactory THz radiation, it would be desirable to provide radiation that is of extremely wide bandwidth for better illuminating materials for analysis by THz cameras and other scanning devices.